Other major cities including Paris, New York and Tokyo already have the technology to prevent mobile blackspots while on their metro systems.

The Financial Times said Transport for London (TfL) and London mayor Sadiq Khan will invite bids from telecoms groups after the General Election next week.

According to the paper, three people familiar with the plans said a "number of companies were vying for the work".

"We are keen to offer mobile phone coverage for our customers. The introduction of this would need to be commercially viable and would follow engagement with staff and customers," a TfL spokesman told the FT.

In March it emerged that plans for a new tunnel-cleaning train to hoover up potentially harmful dust on the London Underground network had been discarded after the project ran into technical difficulties.